Advice On Selecting and Processing Connectors

If you’re reading this, chances are you work with board level interconnects and are familiar with design and processing issues that affect them.

If your job doesn’t require you to work with connectors, but you’re still reading this, then you are probably messed up and need some type of professional help.

Assuming you’re in the first group, check out the list below.

This is from Phil Eckert, Samtec’s Customer Quality Engineering Manager. Phil’s career includes connector design, quality management, and tons of experience processing connectors on boards. IOW, he is familiar with how customers use our connectors in their end-products.

Phil is sharing his advice on points to keep in mind when evaluating, selecting, and processing connectors. These issues probably apply to most board-level interconnect products, whether they come from Samtec or not.

This simple checklist can help you avoid a lot of common issues when selecting and processing your connectors.

We hope you will find it helpful! If you have questions you can contact Phil.

Selecting and Processing Connectors

The longer the connector, the more problems are experienced with coplanarity, soldering, and board-to-board or connector-to-connector alignment.

Follow the recommended footprint and stencil recommendations closely.

Anything added to the base connector is an opportunity for problems. Alignment pins, kapton pads, pick and place pads, end shrouds, etc., all are more prone to issues. If you do not need them, do not ask for them.

Stacking up tolerances is problematic. For example, if you have one long edge card mating into three different connectors, the tolerances can stack up and create mechanical interference problems. If possible, it is better to have three independent edge cards in the example used.

Read the notes carefully on drawings and recommended stencil and PCB layouts.

Most connectors have been tested with soldering; few of these connectors used vapor phase soldering when tested.

If you do not need Au, especially on the solder tails, specify Sn instead. Au in solder joints is more prone to problems when compared to Sn.

Design standoffs that do not interfere with the mated height of the connectors; the Z direction. Standoffs should also allow for the connectors to freely mate in the X and Y directions.

Connectors are made of plastic. Plastic will crack, break, warp, bend, etc if misused. Mating and un-mating at angles tends to promote plastic damage.

The contacts and terminals of connectors are made from very small and thin copper. Abuse will bend these contacts and terminals.

Never pull on the cable to un-mate a cabled connector. When the cable is pulled, unless there is strain relief, the cable is being pulled away from its termination. This is more problematic on non-soldered cable terminations like IDC connectors.

Tape and reel pockets are designed for vacuum pick-up and not grippers. If grippers are used on pick and place equipment, specially design pockets may be needed.

The best predictor of connector performance is normal force. If given the option between two connector series and all other attributes are equal, choose the one with higher normal force. This is important in harsh environments and keenly important if the environment will experience temperature extremes or have high shock and vibration.

Be cautious about relying on a fine pitch connector, those that have a pitch less than .050” (1,27 mm), as being the sole means of mechanical stability between large or heavy PCB assemblies.

Unspent flux is problematic in connectors from both a mechanical interference and corrosive nature.

A SnPb finish is still the superior finish on solder tails and solder paste. Use it if you can.

Search

Get Email Updates

This site uses cookies and other website monitoring technologies to assist with website functions and with our promotional and marketing efforts. By clicking Accept, you consent to the terms in our recently updated Privacy Notice and Privacy Policy.